Book Review - Between Silk and Cyanide, a code makers war

Leo Marks was the principal code-maker for the SOE during the war. This book which is filled with wry humour and bureaucratic frustration covers his war from 1942-45. He was considered the “one who got away” from Bletchley Park, and has amazing insights into the secret war of the SOE.

I have the kindle edition of this book by Leo Marks


In some detail

The book is written with wry humour and honesty. The people he had to work with are not caricatured, but portrayed with refreshing candour (even though I came to intensely dislike some of them!). He is honest about his own failings and worries too.

Aged 20, Leo Marks failed the training course that would have sent him to Bletchley like all his course-mates. He was interviewed by Captain Dancey and was given a test message and asked to break it. They checked him after half an hour and then ninety minutes, and were disappointed he hadn’t completed it. Dancey’s girls completed the work in twenty minutes. At the end of the day he presented them the decrypted message and turned to leave. They told him to leave the code too. “What code, sir” he replied. “The code you broke it with”. “You didn’t give me one sir”. “How did you decode that message if I didn’t give you one?” “You told me to break it sir”. He was really remarkably good.

He learned about the problems with ‘indecipherables’ - whether through morse mangling or mistakes made by the person encoding the message. How those led to requests for retransmission which was doubly dangerous - it kept the agent on the air longer and so made them easier to trace, and it gave the interceptors more tries at the same message, improving their chances of breaking it. So he trained squads of girls to break indecipherables. Kept records of training mistakes. Everything to stop indecipherables.

I particularly liked this quote from an address Marks gave to a new contingent of FANYs, who were going to be working in the code room, trying to break indecipherables:

‘You think you’re tired, don’t you? Then imagine how tired an agent feels who’s had no sleep for three nights and has to encode a message. The Germans are all around her so-called safe house. She has no supervisor to check her coding. All she has is a vital message which she must transmit. Now, I’m going to put a question to this house. Hasn’t that agent a right to make a mistake in her coding? And, if she does, must she pay for it with her life? Must she come on the air again to repeat her message, whilst German direction-finding cars get her bearings? ‘You look puzzled. Is there something you want to ask? No? Perhaps no one’s told you that many of our agents are women? Members of your corps and about your age. I’m thinking of one in particular. Last week the FANYs at Grendon tried four thousand keys to break one of her messages and succeeded on the four thousandth and second…  …a few weeks ago we lost a young Norwegian named Arne Vaerum, code name Penguin. The SS shot him while he was retransmitting an indecipherable message. ‘Must that happen tonight if there’s any chance that you can help us to prevent it? Well you’re going to have that chance!

He was acutely aware of the problems of the poem-code used by SOE. He started the practice of giving people made up poems rather than famous ones, and worked as hard as he could to move people across to WOKs and then LOPs - code practices which he invented.

The WOK would be a Worked-Out Key. Two hundred pre-worked out random keys which were impossible to remember, and would be printed on silk so they wouldn’t be detected if you were patted down. As each key was used it would be cut away from the silk and burned. It wasn’t a code that could be tortured out of a captured agent because he could never know it.

The LOP would be a Letter-Onetime-Pad, a kind of holy grail for securing messages which he worked out how to create.

A large part of the book is concerned with the bureaucratic blockades he found in front of him at every turn, and which he had to navigate around. He found out truths about German interception of codes and agents but nobody wanted to know and he wasn’t able to tell. His frustration was palpable.

There are only a few paragraphs which talk about the love of his life and his devastation when she is killed in an air crash, but it is enough to be very moving:

On Christmas Eve I learned from Ruth’s father that she’d been killed in a plane crash in Canada. I went up to the roof of Norgeby House, which was the closest I could get to her. Someone called out, ‘There’s an idiot on the roof.’ There was a quick way down from it, but she wouldn’t have approved. Looking up at God’s pavement for signs of new pedestrians, I transmitted a message to her which I’d failed to deliver when I’d had the chance:

The life that I have
Is all that I have
And the life that I have is yours.
The love that I have
Of the life that I have
Is yours and yours and yours.
A sleep I shall have
A rest I shall have
Yet death will be but a pause.
For the peace of my years
In the long green grass
Will be yours and yours and yours.

End of sked.

This was the poem which he later gave to Violette Szabo, when training her in coding.

My Opinion

I found this book fascinating, funny and at times desperately sad. I feel for Marks as he knows that the Dutch network is completely blown by the Germans but nobody really believes him and more and more people are sent in to be captured. His humour is ribald and consequently feels very real. He describes scenes with such candour that it is easy to visualise what was going on. Considering that he was doing all this in his early twenties, it is truly astonishing what he was able to accomplish - not just improving the ‘technology’ of codes of the day, but overcoming all obstacles to manage the logistics of obtaining silk, getting codes printed, funding the work which nobody else cared enough about to make it happen.

Why you might want to read this book

There is much written about the breaking of codes by Bletchley Park, but I’ve not read much about the production of codes by the allied forces in WW2, and especially of those codes which have to be used by secret agents in desperate circumstances. The problems of using codes under terribly difficult circumstances and the amazing efforts that were taken by the FANYs to decode the indecipherables was an eye-opener for me. It was really interesting to have the process written down in enough detail that it is possible to try your hand at it yourself. So if you have any interest in secret codes and their usage, there is a lot to learn here.

If you are playing my game, A Cool and Lonely Courage, this book contains some interesting background information to the perils of being a wireless transmitter and coder in the SOE, and especially some of the problems the agents faced because of intransigence or foolishness from the upper echelon of command back at base. It also contains some first hand reminisces about Violette Szabo, Noor Khan and others which is interesting.